Nutrition Considerations in Duchenne Muscular Dystrophy

Effect of Zinc Supplementation on Body Composition of Duchenne Muscular Dystrophy Patients: A Quasi-Experimental Study

Background

The study hypothesized that zinc supplementation would increase or preserve lean body mass in Duchenne muscular dystrophy (DMD) patients. Therefore, we aimed to evaluate the body composition of DMD patients before and after zinc supplementation.

Materials and Methods

The study is a clinical trial comprising 21 boys diagnosed with DMD. Dietary intake parameters were evaluated before zinc supplementation. Serum zinc levels, anthropometry, and body composition were measured in three moments, four months apart. The patients received 5, 10, or 15 mg of zinc bis-glycine supplementation according to age as an oral solution daily for four months. The sample was distributed into two groups according to serum zinc status: zinc deficiency (G1) or adequate zinc (G2).

Results

There was a significant difference in lean body mass between the groups: zinc deficiency (G1) or adequate zinc (G2), at three times (p=0.041, 0.016, and 0.009, respectively). After oral zinc supplementation, serum zinc levels were not different between groups. We did not observe differences when associating the parameters between times and groups.

Conclusion

Zinc supplementation was able to maintain lean body mass and fat mass in patients with DMD with previous deficiencies. Therefore, it is necessary to have a prior screening of serum zinc levels to observe changes after supplementation.

Motor dysfunction of the gut in Duchenne muscular dystrophy: A review

BACKGROUND

Duchenne's muscular dystrophy (DMD) is a severe type of hereditary, neuromuscular disorder caused by a mutation in the dystrophin gene resulting in the absence or production of truncated dystrophin protein. Conventionally, clinical descriptions of the disorder focus principally on striated muscle defects; however, DMD manifestations involving gastrointestinal (GI) smooth muscle have been reported, even if not rigorously studied.

PURPOSE

The objective of the present review is to offer a comprehensive perspective on the existing knowledge concerning GI manifestations in DMD, focusing the attention on evidence in DMD patients and mdx mice. This includes an assessment of symptomatology, etiological pathways, and potential corrective approaches. This paper could provide helpful information about DMD gastrointestinal implications that could serve as a valuable orientation for prospective research endeavors in this field. This manuscript emphasizes the effectiveness of mdx mice, a DMD animal model, in unraveling mechanistic insights and exploring the pathological alterations in the GI tract. The gastrointestinal consequences evident in patients with DMD and the mdx mice models are a significant area of focus for researchers. The exploration of this area in depth could facilitate the development of more efficient therapeutic approaches and improve the well-being of individuals impacted by the condition.

Management of gastrointestinal and nutritional problems in children on home invasive mechanical ventilation

In recent decades, the patient survival is increased due to advances in intensive care units and development of modern mechanic ventilators. Unfortunately, it is not always possible to wean these children from mechanical ventilation. Recently, after placement a tracheostomy tube, these children can be supported at home with noninvasive or invasive mechanical ventilation. Most of the children who need ventilation support at home have neurological impairment. The nutritional issues and gastrointestinal (GI) complications are well defined in critically ill patients, but there are very limited studies on children with tracheostomy. Considering that majority of the patients have neuromuscular disorders, the nutritional and GI problems of the children with tracheostomy are discussed in light of the knowledge of critically ill patients.

Factors influencing the decision to introduce alternative nutrition in patients with Duchenne muscular dystrophy

INTRODUCTION/AIMS

Nutritional management of adults with Duchenne muscular dystrophy (DMD) is an important clinical issue. However, it is not clear which dysphagia-related factors should prompt introduction of alternative nutrition (AN). We aimed to determine which patients with DMD were introduced to AN.

METHODS

This retrospective study included 56 patients with DMD (median age, 23.5 years). They were divided into patients able to continue oral feeding (OF) and those introduced to AN. Body weight, frequency of ventilator use, daily meals, history of steroid treatment, results of videofluoroscopic examination of swallowing (VF), and awareness of dysphagia were evaluated.

RESULTS

Of 56 patients, 19 were in the AN group. After AN introduction, 93% of the patients continued oral intake. The proportion of patients who consumed chopped and liquid diets was higher, and body weight was lower, in the AN than in the OF group. There were no significant differences in age, upper limb function of feeding, frequency of ventilator use, or history of steroid therapy between the two groups. The frequencies of aspiration and residue in the pyriform sinus in VF were higher in the AN group than in the OF group. Decision-tree analysis showed that food form and subjective difficulty swallowing solid foods were the most important factors affecting the decision-making for AN.

DISCUSSION

Patients with DMD who had difficulty eating solid foods were started on AN because they were unable to maintain their weight. These findings provide information for future longitudinal studies to assess the value of AN.

What Nutraceuticals Can Do for Duchenne Muscular Dystrophy: Lessons Learned from Amino Acid Supplementation in Mouse Models

Duchenne muscular dystrophy (DMD), the severest form of muscular dystrophy, is characterized by progressive muscle weakness with fatal outcomes most often before the fourth decade of life. Despite the recent addition of molecular treatments, DMD remains a disease without a cure, and the need persists for the development of supportive therapies aiming to help improve patients' quality of life. This review focuses on the therapeutical potential of amino acid and derivative supplements, summarizing results obtained in preclinical studies in murine disease models. Several promising compounds have emerged, with L-arginine, N-acetylcysteine, and taurine featuring among the most intensively investigated. Their beneficial effects include reduced inflammatory, oxidative, fibrotic, and necrotic damage to skeletal muscle tissues. Improvement of muscle strength and endurance have been reported; however, mild side effects have also surfaced. More explorative, placebo-controlled and long-term clinical trials would need to be conducted in order to identify amino acid formulae that are safe and of true benefit to DMD patients.

Drug development progress in duchenne muscular dystrophy

Duchenne muscular dystrophy (DMD) is a severe, progressive, and incurable X-linked disorder caused by mutations in the dystrophin gene. Patients with DMD have an absence of functional dystrophin protein, which results in chronic damage of muscle fibers during contraction, thus leading to deterioration of muscle quality and loss of muscle mass over time. Although there is currently no cure for DMD, improvements in treatment care and management could delay disease progression and improve quality of life, thereby prolonging life expectancy for these patients. Furthermore, active research efforts are ongoing to develop therapeutic strategies that target dystrophin deficiency, such as gene replacement therapies, exon skipping, and readthrough therapy, as well as strategies that target secondary pathology of DMD, such as novel anti-inflammatory compounds, myostatin inhibitors, and cardioprotective compounds. Furthermore, longitudinal modeling approaches have been used to characterize the progression of MRI and functional endpoints for predictive purposes to inform Go/No Go decisions in drug development. This review showcases approved drugs or drug candidates along their development paths and also provides information on primary endpoints and enrollment size of Ph2/3 and Ph3 trials in the DMD space.

The Role of Taurine in Skeletal Muscle Functioning and Its Potential as a Supportive Treatment for Duchenne Muscular Dystrophy

Taurine (2-aminoethanesulfonic acid) is required for ensuring proper muscle functioning. Knockout of the taurine transporter in mice results in low taurine concentrations in the muscle and associates with myofiber necrosis and diminished exercise capacity. Interestingly, regulation of taurine and its transporter is altered in the mdx mouse, a model for Duchenne Muscular Dystrophy (DMD). DMD is a genetic disorder characterized by progressive muscle degeneration and weakness due to the absence of dystrophin from the muscle membrane, causing destabilization and contraction-induced muscle cell damage. This review explores the physiological role of taurine in skeletal muscle and the consequences of a disturbed balance in DMD. Its potential as a supportive treatment for DMD is also discussed. In addition to genetic correction, that is currently under development as a curative treatment, taurine supplementation has the potential to reduce muscle inflammation and improve muscle strength in patients.

Hepatic Steatosis Assessment as a New Strategy for the Metabolic and Nutritional Management of Duchenne Muscular Dystrophy

Growing evidence suggests that patients with Duchenne muscular dystrophy (DMD) have an increased risk of obesity and metabolic syndrome (MetS). The aim of this study was to investigate the potential risk factors for MetS and hepatic steatosis in patients with different stages of DMD. A total of 48 patients with DMD were enrolled and classified into three stages according to ambulatory status. Body mass index (BMI), serum fasting glucose, insulin, and lipid profiles including triglycerides (TG) and high-density lipoprotein were measured, and the homeostatic model assessment for insulin resistance (HOMA-IR) index was evaluated. Ultrasound examinations of the liver were performed to assess hepatic steatosis using the Nakagami parameter index (NPI). The results showed that BMI, TG, HOMA-IR, and ultrasound NPI differed significantly among DMD stages (p < 0.05). In contrast to the low rates of conventional MetS indices, including disturbed glucose metabolism (0%), dyslipidemia (14.28%), and insulin resistance (4.76%), a high proportion (40.48%) of the patients had significant hepatic steatosis. The ultrasound NPI increased with DMD progression, and two thirds of the non-ambulatory patients had moderate to severe hepatic steatosis. Steroid treatment was a risk factor for hepatic steatosis in ambulatory patients (p < 0.05). We recommend that DMD patients should undergo ultrasound evaluations for hepatic steatosis for better metabolic and nutritional management.

Investigating the Potential for Sulforaphane to Attenuate Gastrointestinal Dysfunction in mdx Dystrophic Mice

Gastrointestinal (GI) dysfunction is an important, yet understudied condition associated with Duchenne muscular dystrophy (DMD), with patients reporting bloating, diarrhea, and general discomfort, contributing to a reduced quality of life. In the mdx mouse, the most commonly used mouse model of DMD, studies have confirmed GI dysfunction (reported as altered contractility and GI transit through the small and large intestine), associated with increased local and systemic inflammation. Sulforaphane (SFN) is a natural isothiocyanate with anti-inflammatory and anti-oxidative properties via its activation of Nrf2 signalling that has been shown to improve aspects of the skeletal muscle pathology in dystrophic mice. Whether SFN can similarly improve GI function in muscular dystrophy was unknown. Video imaging and spatiotemporal mapping to assess gastrointestinal contractions in isolated colon preparations from mdx and C57BL/10 mice revealed that SFN reduced contraction frequency when administered ex vivo, demonstrating its therapeutic potential to improve GI function in DMD. To confirm this in vivo, four-week-old male C57BL/10 and mdx mice received vehicle (2% DMSO/corn oil) or SFN (2 mg/kg in 2% DMSO/corn oil) via daily oral gavage five days/week for 4 weeks. SFN administration reduced fibrosis in the diaphragm of mdx mice but did not affect other pathological markers. Gene and protein analysis revealed no change in Nrf2 protein expression or activation of Nrf2 signalling after SFN administration and oral SFN supplementation did not improve GI function in mdx mice. Although ex vivo studies demonstrate SFN’s therapeutic potential for reducing colon contractions, in vivo studies should investigate higher doses and/or alternate routes of administration to confirm SFN’s potential to improve GI function in DMD.

Nutritional status, swallowing disorders, and respiratory prognosis in adult Duchenne muscular dystrophy patients

Malnutrition and swallowing disorders are common in Duchenne muscular dystrophy (DMD) patients. We assessed, in adult DMD with home mechanical ventilation (HMV) and cough assist device, its prevalence and the relationships with respiratory muscle strength and long-term respiratory prognosis. We reviewed the patients (n = 117, age 18-39 years [median 24]), followed in a reference center, from 2006 to 2015, to obtain clinical baseline, nutritional status, vital capacity (VC), maximal inspiratory pressure (MIP), and maximal expiratory pressure (MEP). The median body mass index (BMI) was low (15.6 kg/m²). Included patients had severe restrictive respiratory function with a median VC of 10.5% [7-17] of the predicted value. All patients were on HMV. Prevalence of malnutrition, swallowing disorders, and gastrostomy were respectively 62%, 34%, and 11%. BMI and serum albumin level were significantly associated with MIP, MEP, and VC. The 1-year/5-years cumulative incidences of respiratory events (pulmonary sepsis and acute respiratory distress) were, respectively, 20.7%/44.5%. Using univariate analysis, predictive factors for respiratory events were swallowing disorders (p = .001), transthyretinemia (p = .034), MIP (p = .039), and MEP (p = .03) but not BMI or albuminemia. Using multivariate analysis, only swallowing disorders remained significantly associated with respiratory events (OR = 4.2, IC 95% 1.31-12.2, p = .01). In conclusion, this study highlights the interrelationships between nutritional intake, swallowing function, airway clearance, and respiratory function in adult DMD. A multidisciplinary approach focusing on these previous factors is essential to optimize DMD patient health.

Bone density and bone health alteration in boys with Duchenne Muscular Dystrophy: a prospective observational study

OBJECTIVES

Boys with Duchenne Muscular Dystrophy (DMD) are at increased risk for compromised bone health, manifesting as low-impact trauma long bone fractures and vertebral compression fractures.

METHODS

In a prospective observational study, we studied bone health parameters in North Indian boys with DMD. We consecutively enrolled ambulatory boys with DMD on glucocorticoid therapy. Bone health was evaluated with X-ray spine, Dual-energy X-ray absorptiometry (DXA), serum calcium, vitamin D3 (25[OH]D), 1,25-dihyroxyvitamin D3 (1,25[OH]₂D₃), serum osteocalcin, osteopontin, and N terminal telopeptide of type 1 collagen (Ntx) levels.

RESULTS

A total of 76 boys with DMD were enrolled. The median age was 8.5 (interquartile range [IQR] 7.04-10.77) years. Among these, seven (9.2%) boys had long bone fractures, and four (5.3%) had vertebral compression fractures. Fifty-four (71%) boys underwent DXA scan, and among these 31 (57%) had low bone mineral density (BMD, ≤-2 z-score) at the lumbar spine. The mean BMD z-score at the lumbar spine was -2.3 (95% confidence interval [CI] = -1.8, -2.8), and at the femoral neck was -2.5 (95% CI = -2, -2.9). 25(OH)D levels were deficient in 68 (89.5%, n=76) boys, and 1,25(OH)₂D₃ levels were deficient in all. Mean serum osteocalcin levels were 0.68 ± 0.38 ng/mL (n=54), serum osteopontin levels were 8.6 ± 4.6 pg/mL (n=54) and serum Ntx levels were 891 ± 476 nmol/L (n=54). Boys with low BMD received glucocorticoids for longer duration, in comparison to those with normal BMD (median, IQR [16.9 (6-34) months vs. 7.8 (4.8-13.4) months]; p=0.04).

CONCLUSIONS

Bone health is compromised in North Indian boys with DMD. BMD at the lumbar spine is reduced in more than half of boys with DMD and nearly all had vitamin D deficiency on regular vitamin D supplements. Longer duration of glucocorticoid therapy is a risk factor for low BMD in our cohort.

β-Glucans as Dietary Supplement to Improve Locomotion and Mitochondrial Respiration in a Model of Duchenne Muscular Dystrophy

Duchenne muscular dystrophy (DMD) is a severe X-linked neuromuscular childhood disorder that causes progressive muscle weakness and degeneration. A lack of dystrophin in DMD leads to inflammatory response, autophagic dysregulation, and oxidative stress in skeletal muscle fibers that play a key role in the progression of the pathology. β-glucans can modulate immune function by modifying the phagocytic activity of immunocompetent cells, notably macrophages. Mitochondrial function is also involved in an important mechanism of the innate and adaptive immune responses, owing to high need for energy of immune cells. In the present study, the effects of 1,3-1,6 β-glucans on five-day-old non-dystrophic and dystrophic (sapje) zebrafish larvae were investigated. The effects of the sonication of β-glucans and the dechorionation of embryos were also evaluated. The results showed that the incidence of dystrophic phenotypes was reduced when dystrophic embryos were exposed to 2 and 4 mg L^-1 of 1,3-1,6 β-glucans. Moreover, when the dystrophic larvae underwent 8 mg L^-1 treatment, an improvement of the locomotor performances and mitochondrial respiration were observed. In conclusion, the observed results demonstrated that 1,3-1,6 β-glucans improve locomotor performances and mitochondrial function in dystrophic zebrafish. Therefore, for ameliorating their life quality, 1,3-1,6 β-glucans look like a promising diet supplement for DMD patients, even though further investigations are required.

Nutraceutical Screening in a Zebrafish Model of Muscular Dystrophy: Gingerol as a Possible Food Aid

Duchenne muscular dystrophy (DMD), caused by mutations in the dystrophin gene, is an inherited neuromuscular disorder that causes loss of muscle mass and motor skills. In the era of genomic medicine, there is still no known cure for DMD. In clinical practice, there is a growing awareness of the possible importance of nutrition in neuromuscular diseases. This is mostly the result of patients’ or caregivers’ empirical reports of how active substances derived from food have led to improved muscle strength and, thus, better quality of life. In this report, we investigate several nutraceutical principles in the sapje strain of zebrafish, a validated model of DMD, in order to identify possible natural products that, if supplemented in the diet, might improve the quality of life of DMD patients. Gingerol, a constituent of fresh ginger, statistically increased the locomotion of mutant larvae and upregulated the expression of heme oxygenase 1, a target gene for therapy aimed at improving dystrophic symptoms. Although three other compounds showed a partial positive effect on locomotor and muscle structure phenotypes, our nutraceutical screening study lent preliminary support to the efficacy and safety only of gingerol. Gingerol could easily be proposed as a dietary supplement in DMD.

Growth and nutrition in pediatric neuromuscular disorders

BACKGROUND & AIMS

Little is currently known about the nutrition and growth outcomes in children with neuromuscular disorders (NMDs), and these are likely disease dependent. The aim of this study was to describe the range of nutritional issues in pediatric NMDs and identify similarities and differences in growth outcomes and nutritional needs in children with a variety of NMDs at different ages, with the goal of informing future services.

METHODS

In this cross-sectional study we collected data on growth, dietetic interventions and nutrition-related issues in 160 children who attended a multidisciplinary clinic in a tertiary children's hospital, from February to December 2019. Children with significant weakness affecting mobility before the age of 3 years were clinically grouped into 'early-onset NMDs'.

RESULTS

Across our clinic, 42.5% children had a history of chronic gastrointestinal issues, and 34.4% received dietetic care on the day of clinical visit. Children with early-onset NMDs had significantly higher prevalence of swallowing issues, gastroesophageal reflux, and vomiting, as well as higher frequency of dietetic consultations, high energy diet, swallowing assessment and tube-feeding, compared to later-onset NMDs (p < 0.05). In total, 49.2% children with NMDs had an abnormal weight, in which the prevalence of underweight (n = 24, 19.2%) was significantly higher compared to normal Australian children (8.2%) (p < 0.05). In Duchenne muscular dystrophy, over 50% children were overweight/obese.

CONCLUSION

Among children with NMDs, there were many disease-specific nutrition-related symptoms, growth issues, and dietetic practices that were tailored to individual needs. Future studies should focus on measuring the impact of specific dietetic practices on growth and nutritional outcomes, as well as developing a precision medicine approach tailored to the individual nutritional needs of children with NMDs.

Respiratory decline in adult patients with Becker muscular dystrophy: A longitudinal study

Becker muscular dystrophy (BMD) is a rare hereditary neuromuscular disease, caused by a genetic defect in the Duchenne Muscular Dystrophy (DMD) gene. We studied the natural history of respiratory function and its affecting factors in 23 adult BMD patients. These important data are needed for (future) clinical trials in BMD but are largely lacking. Patients had a median age of 51 years (28-78y) and median follow-up duration of 14 years (2-25y). We analysed 190 pulmonary function measurements with a median interval of one year (1-17y) and measured a 1.00% decline of Forced Vital Capacity percent predicted (FVC%pred) per year (p = 0.004). Loss of ambulation significantly increased the annual rate of FVC decline and was dependent of patient's body mass index (BMI; p = 0.015), with increases in BMI correlating with an even more rapid deterioration of FVC. A decline in Medical Research Council (MRC) sum score was significantly correlated with a decline in FVC (p = 0.003). We conclude that adult BMD patients experience a significant but mild respiratory decline. However, this decline is significantly more rapid and clinically relevant after loss of ambulation, which warrants a more vigilant follow-up of respiratory function in this subgroup.

Validity of bioelectrical impedance to estimate fat-free mass in boys with Duchenne muscular dystrophy

The evaluation of fat-free mass (FFM) in patients with Duchenne muscular dystrophy (DMD) is useful to investigate disease progression and therapeutic efficacy. This study aimed to validate the Bioelectrical impedance (BIA) method compared with the dual-energy X-ray absorptiometry (DXA) for estimating the %FFM in boys with DMD. This is a cross-sectional study performed with children and adolescents diagnosed with DMD. Resistance and reactance were measured with a BIA analyzer, from which eight predictive equations estimated the %FFM. The %FFM was also determined by DXA and its used as a reference method. Pearson correlation test, coefficient of determination, the root-mean-square error, the interclass correlation coefficient, and linear regression analysis were performed between %FFM values obtained by BIA and DXA. The agreement between these values was verified with the Bland-Altman plot analysis. Forty-six boys aged from 5 to 20 years were enrolled in the study. All the equations showed a correlation between the %FFM estimated by BIA and determined by DXA (p < 0.05). The Bland-Altman method indicated that two equations have a significant bias (p < 0.05) and six equations showed no significant bias of %FFM (p > 0.05). However, one of them has high variation and wide limits of agreement. Five of eight %FFM predictive equations tested in DMD were accurate when compared with the DXA. It can be concluded that BIA is a validity method to evaluate patients with DMD.

Relationship between Eating and Digestive Symptoms and Respiratory Function in Advanced Duchenne Muscular Dystrophy Patients

Background:

Duchenne muscular dystrophy (DMD) patients can have various issues that affect their quality of life, including eating and digestive conditions.

Objective:

We sought to identify the relationship between respiratory function and various eating and digestion related symptoms in patients with advanced Duchenne muscular dystrophy (DMD).

Methods:

Eating and digestive symptoms, including loss of appetite, nausea, vomiting, diarrhea, constipation, swallowing difficulty, mastication difficulty, early satiety, and aspiration, were evaluated among patients with advanced DMD who were nonambulatory and required noninvasive mechanical ventilatory support. In addition, various respiratory function parameters were measured, including forced vital capacity (FVC), maximal insufflation capacity (MIC), peak cough flow (PCF), assisted PCF (APCF), maximal inspiratory pressure (MIP), and maximal expiratory pressure (MEP). We then analyzed the relationship between gastrointestinal symptoms and respiratory function parameters.

Results:

A total of 180 patients (age, 22.3±5.0 years) were included in the analysis. Loss of appetite and early satiety showed no correlation with any of the respiratory function parameters. Constipation was correlated with MEP; swallowing difficulty was correlated with MIC, APCF, MIP and MEP; and mastication difficulty was correlated with FVC, PCF, APCF, MIP, and MEP. Notably, age did not correlate with any gastrointestinal symptoms.

Conclusions:

Eating and digestive symptoms are more closely correlated with respiratory function than with age in patients with DMD. We think this correlation is mainly caused by the skeletal muscle strength, which is major determinant of both digestive and respiratory function.

The adult multidisciplinary respiratory neuromuscular clinic

Many neuromuscular disorders (NMD) are complicated by respiratory failure. These patients are best managed in a multidisciplinary outpatient clinic to provide timely access to the various disciplines they require. The key mainstay of treatment of respiratory failure in patients with NMD is noninvasive ventilation, supported by secretion clearance, speech and language therapy, optimisation of nutrition and the maintenance of mobility. Patients with specific conditions may also require cardiology, neurology, orthopaedics, urology and psychological services. The respiratory NMD multidisciplinary team should also provide access to palliative care, and caregiver health and wellbeing should also be reviewed at clinical reviews. The future of care for the respiratory NMD patient will increasingly involve home services and telehealth and the clinic should be equipped and resourced to deliver these. Although not all health systems will be able to provide all elements of the multidisciplinary team discussed here, this review provides the “ideal” recipe for the adult multidisciplinary team and the evidence base underpinning this from which a clinic can be developed.

Care for neuromuscular-related respiratory failure is complex and is best delivered in a multidisciplinary context. The future will increasingly involve home services and telehealth, and their burden needs to be considered when establishing this service.https://bit.ly/33fNsMT

Nutritional practices in pediatric patients with neuromuscular disorders

Children with neuromuscular disorders (NMDs) may experience a spectrum of nutritional issues with adverse health consequences. This review summarizes the current understanding of nutritional care in pediatric NMDs, recognizing disease-specific aspects of nutrition alongside the challenges and needs in dietetic care. General or disease-related nutritional issues for children with NMDs include being underweight, overweight, or obese and having swallowing difficulty, gastroesophageal reflux, diarrhea, and/or constipation. Specific challenges in NMD nutritional assessment include alterations in body composition and energy requirements and difficulties in measuring anthropometry. Multidisciplinary dietetic intervention focuses on optimizing nutrient intakes to avert growth failure or obesity and managing feeding difficulties and gastrointestinal problems. Care guidelines are disease specific and vary in approach and detail. To promote best clinical practice across diverse settings, a standardized approach to assessing growth and nutrition across all pediatric NMDs is needed to direct optimal care centered on individual requirements. Future studies should focus on determining the prevalence of specific nutritional issues and the effectiveness of specific interventions among various pediatric NMD populations.

High prevalence of plasma lipid abnormalities in human and canine Duchenne and Becker muscular dystrophies depicts a new type of primary genetic dyslipidemia

BACKGROUND

Duchenne muscular dystrophy (DMD) and Becker muscular dystrophy (BMD) are allelic X-linked recessive muscle diseases caused by mutations in the DMD gene, with DMD being the more severe form. We have recently shown that increased plasma low-density lipoprotein-associated cholesterol causes severe muscle wasting in the mdx mouse, a mild DMD model, which suggested that plasma lipids may play a critical role in DMD. We have also observed that loss of dystrophin in mice causes unexpected elevations in plasma lipoprotein levels.

OBJECTIVE

The objectives of the study were to determine whether patients with DMD and BMD also present with clinically relevant plasma lipoprotein abnormalities and to mitigate the presence of confounders (medications and lifestyle) by analyzing the plasma from patients with DMD/BMD and unmedicated dogs with DMD, the most relevant model of DMD.

METHODS

Levels of low-density lipoprotein-associated cholesterol, high-density lipoprotein cholesterol, and triglycerides were analyzed in patients with DMD and BMD and female carriers. Samples from unmedicated, ambulatory dogs with DMD, unaffected carriers, and normal controls were also analyzed.

RESULTS

We report that 97% and 64% of all pediatric patients with DMD (33 of 36) and BMD (6 of 11) are dyslipidemic, along with an unusually high incidence in adult patients with BMD. All dogs with DMD showed plasma lipid abnormalities that progressively worsened with age. Most strikingly, unaffected carrier dogs also showed plasma lipid abnormalities similar to affected dogs with DMD. Dyslipidemia is likely not secondary to liver damage as unaffected carriers showed no plasma aminotransferase elevation.

CONCLUSIONS

The high incidence of plasma lipid abnormalities in dystrophin-deficient plasma may depict a new type of genetic dyslipidemia. Abnormal lipid levels in dystrophinopathic samples in the absence of muscle damage suggest a primary state of dyslipidemia. Whether dyslipidemia plays a causal role in patients with DMD warrants further investigation, which could lead to new diagnostic and therapeutic options.

Effects of Traction on Interpretation of Lumbar Bone Mineral Density in Patients with Duchenne Muscular Dystrophy: A New Measurement Method and Diagnostic Criteria Based on Comparison of Dual-Energy X-Ray Absorptiometry and Quantitative Computed Tomography

INTRODUCTION

This study aimed to compare the performance of dual-energy X-ray absorptiometry (DXA) and quantitative computed tomography (QCT) in evaluating bone mineral density (BMD) of patients with Duchenne muscular dystrophy and scoliosis.

METHODOLOGY

Twenty-nine participants (mean age 19.72 ± 6.13 years) underwent whole spine radiography, DXA before and after traction, and QCT alone without traction. Scoliosis and vertebral rotation angles obtained before and after traction were compared, and BMD values from DXA were compared to those obtained via QCT. The scoliosis angle, presented as Cobb's angle of L1-L4, was measured.

RESULTS

Cobb's angle significantly decreased from 30.38° ± 24.83° before traction to 22.78° ± 20.41° after traction (p < 0.0001) and the Z-score decreased from -1.88 ± 1.59 to -2.86 ± 2.16 (p < 0.0001). Changes in rotation angle, BMD, and bone mineral content were not significant. Post-traction BMD values and Z-scores showed a higher correlation with QCT measurements than pretraction. Moreover, pre and post-traction Z-scores (≤-1.1 and -1.36, respectively) were more accurate in identifying patients with osteoporosis according to QCT scans compared with the preexisting Z-score of -2 or less.

CONCLUSION

Lumbar BMD measured via DXA and scoliosis allowed a more accurate diagnosis of osteoporosis when traction was applied.

A modified diet does not ameliorate muscle pathology in a mouse model for Duchenne muscular dystrophy

Duchenne muscular dystrophy (DMD) is caused by a lack of dystrophin protein. Next to direct effects on the muscles, this has also metabolic consequences. The influence of nutrition on disease progression becomes more and more recognized. Protein intake by DMD patients may be insufficient to meet the increased demand of the constantly regenerating muscle fibers. This led to the hypothesis that improving protein uptake by the muscles could have therapeutic effects. The present study examined the effects of a modified diet, which composition might stimulate muscle growth, on disease pathology in the D2-mdx mouse model. D2-mdx males were fed with either a control diet or modified diet, containing high amounts of branched-chain amino acids, vitamin D3 and ursolic acid, for six weeks. Our study indicates that the modified diet could not ameliorate the muscle pathology. No effects on bodyweight or weight of individual muscles were observed. Neither did the diet affect severity of fibrosis or calcification of the muscles.

Body composition and body mass index in Duchenne muscular dystrophy: Role of dietary intake

INTRODUCTION

In Duchenne muscular dystrophy (DMD) muscle is replaced by adipose tissue. The role of dietary intake (DI) in DMD has not been evaluated. In this study we examined body composition, body mass index (BMI), and adequacy of DI in patients with DMD and evaluated the influence of DI on body composition.

METHODS

Patients (n = 101; age 3-18 years; BMI 11.8-29.5 kg/m² ) completed a dietary recall to determine DI and then underwent dual-energy X-ray absorptiometry to determine body composition.

RESULTS

Preschool-age and school-age boys with DMD had high total energy intake. Protein intake per kilogram exceeded recommendations. As age increased, the percentage of boys with abnormal BMI and fat mass increased, while lean mass decreased. Dietary intake did not predict body fat or lean mass.

DISCUSSION

Age-dependent changes in BD in boys with DMD may be due to endogenous metabolic factors related to the underlying disease process and to disease-related mobility impairments. Muscle Nerve 59:295-302, 2019.

Effects of metformin on congenital muscular dystrophy type 1A disease progression in mice: a gender impact study

Congenital muscular dystrophy with laminin α2 chain-deficiency (LAMA2-CMD) is a severe muscle disorder with complex underlying pathogenesis. We have previously employed profiling techniques to elucidate molecular patterns and demonstrated significant metabolic impairment in skeletal muscle from LAMA2-CMD patients and mouse models. Thus, we hypothesize that skeletal muscle metabolism may be a promising pharmacological target to improve muscle function in LAMA2-CMD. Here, we have investigated whether the multifunctional medication metformin could be used to reduce disease in the dy^2J/dy^2J mouse model of LAMA2-CMD. First, we show gender disparity for several pathological hallmarks of LAMA2-CMD. Second, we demonstrate that metformin treatment significantly increases weight gain and energy efficiency, enhances muscle function and improves skeletal muscle histology in female dy^2J/dy^2J mice (and to a lesser extent in dy^2J/dy^2J males). Thus, our current data suggest that metformin may be a potential future supportive treatment that improves many of the pathological characteristics of LAMA2-CMD.

Nutritional and Gastrointestinal Management of the Patient With Duchenne Muscular Dystrophy

Advances in treatment and multidisciplinary management have resulted in improved survival of individuals with Duchenne muscular dystrophy (DMD). Updated DMD treatment recommendations as found in the 2018 DMD Care Considerations are aimed to assist multidisciplinary care teams in providing standardized care to their patients, including attention to nutritional and gastrointestinal health. Challenges remain for care teams in accurately estimating height and nutritional status for individuals with DMD. It can be difficult for patients to maintain a healthy weight. Risk factors for obesity include glucocorticoid therapy and loss of ambulation. In contrast, in the later stages of the disease, swallowing dysfunction can lead to poor nutrition and consideration for gastrostomy tube placement. Constipation is highly prevalent, underrecognized, and undertreated in DMD. With this article, we address the assessment and management of gastrointestinal and nutritional issues, as well as clinical controversies.

Clinical management of Duchenne muscular dystrophy: the state of the art

INTRODUCTION

Duchenne muscular dystrophy (DMD) is a devastating, progressive neuromuscular disorder for which there is no cure. As the dystrophin gene is located on the X chromosome, DMD occurs predominately in males. DMD is caused by a lack of functional dystrophin protein resulting from mutations in the 2.2-Mb DMD gene, whichdisrupts the reading frame. Care considerations for DMD advocate a coordinated, multidisciplinary approach to the management of DMD in order to optimize management of the primary manifestations of DMD as well as any secondary complications that may arise.

METHODS

This review provides an overview of the multidisciplinary clinical management of DMD with regard to the respiratory, cardiology, orthopedic, and nutritional needs of patients with DMD. Recent advances in novel disease-modifying treatments for DMD are also discussed with specific reference to exon skipping and suppression of premature stop codons as promising genetic therapies.

RESULTS

The combination of multidisciplinary clinical management alongside novel gene therapiesoffers physicians a powerful armamentarium for the treatment of DMD.

Skeletal Muscle Metabolism in Duchenne and Becker Muscular Dystrophy-Implications for Therapies

The interactions between nutrition and metabolism and skeletal muscle have long been known. Muscle is the major metabolic organ&mdash;it consumes more calories than other organs&mdash;and therefore, there is a clear need to discuss these interactions and provide some direction for future research areas regarding muscle pathologies. In addition, new experiments and manuscripts continually reveal additional highly intricate, reciprocal interactions between metabolism and muscle. These reciprocal interactions include exercise, age, sex, diet, and pathologies including atrophy, hypoxia, obesity, diabetes, and muscle myopathies. Central to this review are the metabolic changes that occur in the skeletal muscle cells of muscular dystrophy patients and mouse models. Many of these metabolic changes are pathogenic (inappropriate body mass changes, mitochondrial dysfunction, reduced adenosine triphosphate (ATP) levels, and increased Ca²⁺) and others are compensatory (increased phosphorylated AMP activated protein kinase (pAMPK), increased slow fiber numbers, and increased utrophin). Therefore, reversing or enhancing these changes with therapies will aid the patients. The multiple therapeutic targets to reverse or enhance the metabolic pathways will be discussed. Among the therapeutic targets are increasing pAMPK, utrophin, mitochondrial number and slow fiber characteristics, and inhibiting reactive oxygen species. Because new data reveals many additional intricate levels of interactions, new questions are rapidly arising. How does muscular dystrophy alter metabolism, and are the changes compensatory or pathogenic? How does metabolism affect muscular dystrophy? Of course, the most profound question is whether clinicians can therapeutically target nutrition and metabolism for muscular dystrophy patient benefit? Obtaining the answers to these questions will greatly aid patients with muscular dystrophy.

Greater Colo-Rectal Activation Phenotype in Exercised mdx Mice

Introduction

Duchenne Muscular Dystrophy is a genetic disease that is caused by a deficiency of dystrophin protein. Both Duchenne Muscular Dystrophy patients and dystrophic mice suffer from intestinal dysfunction.

Methods

The present study arose from a chance observation of differences in fecal output of dystrophic vs. normal mice during 20-minutes of forced continuous treadmill exercise. Here, we report on the effects of exercise on fecal output in two different dystrophic mutants and their normal background control strains. All fecal materials evacuated during exercise were counted, dried and weighed.

Results

Mice of both mutant dystrophic strains produced significantly more fecal material during the exercise bout than the relevant control strains.

iscussion

We propose that exercise--induced Colo--Rectal Activation Phenotype test could be used as a simple, highly sensitive, non-invasive biomarker to determine efficacy of dystrophin replacement therapies.

Diagnosis and management of Duchenne muscular dystrophy, part 1: diagnosis, and neuromuscular, rehabilitation, endocrine, and gastrointestinal and nutritional management

Since the publication of the Duchenne muscular dystrophy (DMD) care considerations in 2010, multidisciplinary care of this severe, progressive neuromuscular disease has evolved. In conjunction with improved patient survival, a shift to more anticipatory diagnostic and therapeutic strategies has occurred, with a renewed focus on patient quality of life. In 2014, a steering committee of experts from a wide range of disciplines was established to update the 2010 DMD care considerations, with the goal of improving patient care. The new care considerations aim to address the needs of patients with prolonged survival, to provide guidance on advances in assessments and interventions, and to consider the implications of emerging genetic and molecular therapies for DMD. The committee identified 11 topics to be included in the update, eight of which were addressed in the original care considerations. The three new topics are primary care and emergency management, endocrine management, and transitions of care across the lifespan. In part 1 of this three-part update, we present care considerations for diagnosis of DMD and neuromuscular, rehabilitation, endocrine (growth, puberty, and adrenal insufficiency), and gastrointestinal (including nutrition and dysphagia) management.

Nutritional Challenges in Duchenne Muscular Dystrophy

Neuromuscular diseases (NMDs) represent a heterogeneous group of acquired or inherited conditions. Nutritional complications are frequent in NMDs, but they are sometimes underestimated. With the prolongation of survival in patients with NMDs, there are several nutritional aspects that are important to consider, including the deleterious effects of overnutrition on glucose metabolism, mobility, and respiratory and cardiologic functions; the impact of hyponutrition on muscle and ventilatory function; constipation and other gastrointestinal complications; chewing/swallowing difficulties with an increased risk of aspiration that predisposes to infectious diseases and respiratory complications; as well as osteoporosis with an associated increased risk of fractures. The aim of this review is to provide a comprehensive analysis of the nutritional aspects and complications that can start in children with Duchenne muscular dystrophy (DMD) and increase with ageing. These aspects should be considered in the transition from paediatric clinics to adult services. It is shown that appropriate nutritional care can help to improve the quality of life of DMD patients, and a multidisciplinary team is needed to support nutrition challenges in DMD patients. However, studies on the prevalence of overnutrition and undernutrition, gastrointestinal complications, infectious diseases, dysphagia, and reduced bone mass in the different types of NMDs are needed, and appropriate percentiles of weight, height, body mass index, and body composition appear to be extremely important to improve the management of patients with NMD.

Secondary Conditions Among Males With Duchenne or Becker Muscular Dystrophy

Duchenne and Becker muscular dystrophy are X-linked neuromuscular disorders characterized by progressive muscle degeneration. Despite the involvement of multiple systems, secondary conditions among affected males have not been comprehensively described. Two hundred nine caregivers of affected males (aged 3-31 years) identified by the Muscular Dystrophy Surveillance, Tracking, and Research Network completed a mailed survey that included questions about secondary conditions impacting multiple body functions. The 5 most commonly reported conditions in males with Duchenne were cognitive deficits (38.4%), constipation (31.7%), anxiety (29.3%), depression (27.4%), and obesity (19.5%). Higher frequencies of anxiety, depression, and kidney stones were found among nonambulatory males compared to ambulatory males. Attention-deficit hyperactivity disorder (ADHD) was more common in ambulatory than nonambulatory males. These data support clinical care recommendations for monitoring of patients with Duchenne or Becker muscular dystrophy by a multidisciplinary team to prevent and treat conditions that may be secondary to the diagnosis.